Flowable food products, such as margarine, butter, or the like are typically packaged in individual containers for retail sale and consumer use. Packaging of these types of food products is ordinarily effected with the use of fill pump devices which are operated in conjunction with associated conveyors which move containers for filling relative to the filling devices. In this manner, the containers are presented in a continuous, sequential manner to the filling devices, with the devices operated to dispense the desired quantity of food product to each of the containers.
As will be appreciated, precise control of the filling devices is necessary in order to assure that each container receives the desired quantity of product. In practice, such precision can be difficult to achieve. In addition to the usual fluctuations in product consistency and temperature, the periodic start-up and shut-down of a filling line typically complicates accurate filling.
In the past, two types of filling systems have generally been employed. Pneumatically controlled systems typically include pneumatically-actuated pumping devices for dispensing the food product into the associated containers. These devices offer the distinct advantage of permitting the product piston of the typical food product pump to be advanced at a relatively constant speed during its advancing, container-filling stroke, irrespective of the overall cycle speed of the device. This has been found to be particularly advantageous in providing oil-based food products with the desired uniform appearance.
On balance, such pneumatic systems can be problematical due to the inevitable fluctuations in air supply pressure, the limited service life of the usual pneumatic cylinders, and the attendant problems of maintaining the various seals and like components of such a system. In summary, these types of systems do not provide the desired degree of dependability, resulting in undesirable down time, and can undesirably result in fluctuating weight control.
In contrast, the other type of typical food product filling system is cam-operated, and is ordinarily mechanically linked to the drive for the associated container conveyor. Cam operation of the food product pump of this type of system has been found to desirably provide superior weight control, when compared to pneumatic systems, and desirably consistent operation of the pump devices. This type of system desirably avoids problems associated with fluctuations in product supply pressure and air supply pressure, and imprecise operator control.
Despite certain advantages, such cam-operated systems cannot deliver the desired pump piston velocity during initial start-up of the filling line, which can adversely affect the appearance of the food product with which the containers are being filled. Additionally, such systems lack versatility, since typically the system performs optimally within a limited speed range, and thus does not lend itself to running at higher or lower speeds. When the system is run at other than its optimal speed, undesirably high product reject rates result.
The present invention seeks to overcome the disadvantages associated with filling systems heretofore employed by permitting versatile operation of a filling system while maintaining the desired quality of product appearance under a wide variety of operating conditions.